/Engine/Source/Runtime/Engine/Public/AnimationRuntime.h
Calculate the component-space bone transform for the specified bone. This is similar toGetComponentSpaceTransform(), but uses a cached array of transforms to prevent re-calculations when requesting transforms for multiple bones with shared parents. This is only likely to be more efficient than FillUpComponentSpaceTransforms if you only need a relatively small number of bone transforms.
static const FTransform & GetComponentSpaceTransformWithCache ( const [FReferenceSkeleton](API\Runtime\Engine\FReferenceSkeleton) & InRefSkeleton, const [TArray](API\Runtime\Core\Containers\TArray)< FTransform > & InBoneSpaceTransforms, int32 BoneIndex, [TArray](API\Runtime\Core\Containers\TArray)< FTransform > & CachedTransforms, [TArray](API\Runtime\Core\Containers\TArray)< bool > & CachedTransformReady )